WATER DISTRIBUTION SYSTEM DESIGN AND ?· water distribution system design and specifications----- section…

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  • WATER DISTRIBUTION

    SYSTEM DESIGN

    AND

    SPECIFICATIONS

    -----------------------------------------------------------------

    SECTION 12

    Revised August 4, 2017

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    WATER DISTRIBUTION SYSTEM DESIGN

    AND SPECIFICATIONS

    -----------------------------------------------------------------

    12.01 General

    12.02 Water Main Materials

    12.03 Water Main Locations

    12.04 Water Main Grades

    12.05 Protection of Water Supplies

    12.06 Pipe Fitting Specifications

    12.07 Dead Ends

    12.08 Thrust Blocking

    12.09 Trench Depth

    12.10 Proper Backfilling

    12.11 Setting Valves

    12.12 Valve Specifications

    12.13 Setting Fire Hydrants

    12.14 Fire Hydrant Specifications

    12.15 Manhole Castings

    12.16 Valve Boxes

    12.17 Restrained Glands

    12.18 Service Connections

    12.19 Tracer Wire for PVC and HDPE Services

    12.20 Copper Tubing Specifications

    12.21 Copper Compression Joint Specifications

    12.22 Corporation Stop Valve Specifications

    12.23 Curb Stop Valve Specifications

    12.24 Curb Stop Box Specifications

    12.25 Service Saddle Specifications

    12.26 Service Fitting Specifications

    12.27 Horizontal Directional Boring

    12.28 Hydrostatic Testing

    12.29 Disinfection

    12.30 Miscellaneous Fittings & Connections

    12.31 Polyethylene Encasement of Water main

    12.32 High Density Polyethylene (HDPE) Pipe

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    12.01 General

    Water mains, service connections and appurtenances shall be constructed in accordance with

    American Water Works Association (AWWA) Standard C600 as amended herein. Subjects not governed by the above shall be governed by the pertinent provisions of the following, listed in order of precedence:

    (a) Great Lakes - Upper Mississippi River Board of State Sanitary Engineers

    Recommended Standards for Water Works, latest revision.

    (b) Standard Specifications for Water and Sewer Main Construction in Illinois, latest revision.

    Construction standards and all materials not addressed herein, but used in water distribution

    construction shall comply with the Rockford Water Division Specifications available from the water utility. Manufacturers and/or their suppliers will be required to provide a statement indicating that all components they provide are "American Made". Failure to provide certification shall be cause for rejection. All brass fittings and valves for service lines shall be manufactured in accordance with AWWA Standard C-800, latest revision. Any brass part of the fitting or valve in contact with potable water shall be made of a No-Lead Brass, defined for this specification as UNS Copper Alloy No. C89520 or C89833 in accordance with the chemical and mechanical requirements of ASTM B584 and AWWA C-800. This No-Lead Brass alloy shall not contain more than nine one hundredths of one percent (0.09% or less) total lead content by weight.

    Any Brass part of the fitting or valve not in contact with potable water shall be made of 85-5-5- 5 brass as defined for this specification as UNS Copper Alloy C83600 per ASTM B62, ASTM B584 and AWWA C-800. All brass fittings and valves shall be certified by an ANSI accredited test lab per NSF/ANSI Standard 61, Drinking Water Components Health Effects, Section 8 or NSF/ANSI Standard 372, Drinking Water System Components Lead Content. Proof of certification is required. Brass fittings and valves shall comply with the United States Of America Safe Drinking Water Act, and the U.S. Environmental Protection Agency. All brass fittings and valves shall have the manufacturers name or trademark permanently stamped or cast on it. Another marking identifying the no lead brass alloy, e.g., NL, shall be cast or permanently stamped on the fitting or valve. Certificates of compliance with these specifications shall be provided with all materials supplied. Failure to conform to these specifications or failure to provide the required certification shall be cause for rejection of materials.

    12.02 Water Main Materials

    All water mains shall conform to AWWA Standard C151 & C111 and, be constructed of

    Class 52 Ductile Iron pipe for all sizes through twelve (12) inch, and Class 51 Ductile Iron pipe for all sizes larger. Other materials may be allowed upon the review and approval by the City Engineer or his designee. If approved for use, High Density Polyethylene (HDPE) shall conform to AWWA Standard C906. All pipe, shall be cement mortar lined inside, conforming

    to AWWA Standard C104, and bituminous coated on the outside. The exterior of ductile iron pipe shall be coated with a layer of arc-sprayed zinc per ISO 8179. The mass of the zinc applied shall be 200 g/m2 of pipe surface area. A finishing layer topcoat shall be applied to the zinc. The mean dry film thickness of the finishing layer shall not be

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    less than 3 mils with a local minimum not less than 2 mils. The coating system shall conform in every respect to ISO 8179-1 "Ductile iron pipes - External zinc-based coating - Part 1: Metallic zinc with finishing layer. Second edition 2004-06-01." Pipe-to-pipe joints on straight runs of main shall be push-on type with the exception of submerged river crossings or other special applications. Approval of joints in those situations

    will be made by the Rockford Water Division. All joints on fittings, valves, and bends, shall be mechanical type with ductile iron retainer glands. To ensure electrical conductivity, brass wedges MUST be used with push on joints in accordance with Section 41-2.05D of the Standard Specifications for Sewer and Water in Illinois. All mechanical joints shall be tightened to the manufacturers specification using a torque stick. Pressure connections or wet tap connections will not be permitted if the existing main is the same size or smaller than the proposed main that is to tee into the existing (example an 8 pressure connection will not be allowed on an 8 existing water main). All mains shall be a minimum of eight (8) inch nominal diameter. Larger sizes will be required when needed to satisfy local water demand, fire flows, and/or transmission lines. Water mains shall be designed using standard pipe sizes of 8", 12", 16", 20", 24, 30 and 36" nominal diameter. When design calculations yield an intermediate pipe size the next larger standard size shall be used. Water mains shall be sized so that the pressure at maximum flow conditions is at least twenty-five (25) psig in all parts of the distribution system. In addition, the velocity at maximum flow must be no more than ten (10) fps. Friction losses shall be calculated by the Hazen-Williams formula, using a friction coefficient (C) of 100.

    Static head and distribution system, flow characteristics can be, acquired from the Rockford

    Water Division.

    12.03 Water Main Locations

    Water mains shall, in general, be located between the curb and sidewalk. Preferred locations

    are shown on detailed drawings that can be obtained from the Rockford Water Division. Water mains parallel to curbs shall be located at least two (2) feet from the back of the curb. All water mains shall be looped except where cul-de-sacs can be served by mains five hundred (500) feet or less in length.

    a.) Water mains shall be constructed within the public Right-Of-Way whenever possible. b.) When it is necessary to construct a water main on private property, an exclusive water

    main easement shall be granted to the Water Division, extending a minimum of ten (10) feet on either side of the main and shall be recorded with the final plat.

    c.) No water main shall be laid under, nor within ten (10) feet of, any building or permanent

    structure. d.) Water main that connects to an existing public water main at two locations or more

    (looped), and/or has multiple services tapped off of it, shall be public water main.

    12.04 Water Main Grades

    Water mains shall be laid at a uniform grade between main junctures. Where a uniform grade is not possible, the grade shall be designed so that the number of changes in the direction of slope are the minimum possible.

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    a.) Where both ends of a section of main are at a lower elevation than an intermediate point, a means of releasing entrapped air (e.g. fire hydrant, air release valve) must be provided at the top of the "hill".

    b.) Where both ends of a section of main are at a higher elevation than an intermediate

    point, a means of flushing out sediment through a fire hydrant must be provided at the bottom of the "valley."

    The minimum radii of curves which may be laid by deflecting twenty (20) foot lengths of push-on joint pipe at the joints are:

    8" - 230' radius 12" - 230' radius 16" - 380' radius 20" - 380' radius 24" - 380' radius 30 - 380 radius 36 - 380 radius

    a.) Curve radii shall be measured in the plane defined by centerlines of the pipe. b.) Curves with smaller radii than permitted above shall be made using bends and offsets.

    12.05 Protection of Water Supplies

    No water main shall pass through or come into contact with any part of a sewer manhole or storm sewer inlet structure. Horizontal and vertical separation between water mains, water appurtenances and all storm and sanitary sewers, and appurtenances, or other sewerage structures shall be as follows:

    a.) Whenever possible, water mains shall be laid no less than ten (10) feet horizontally from any existing or proposed drain, storm sewer, sanitary sewer, combined sewer or sewer service connection.

    b.) When it is impossible to accomplish a ten (10) feet horizontal separation between a

    water main and a sewer, the bottom of the water main must be at least eighteen (18) inches above the top of the sewer and the water main and sewer must be constructed in separate trenches. Where separate trenches are not possible, the water main must be constructed on a shelf of undisturbed earth located as far as possible from the sewer.

    c.) When it is impossible to accomplish the separations required above, both the water

    main and the sewer must be constructed of water main materials and the sewer must be pressure tested for water tightness at the maximum expected surcharge head before backfilling.

    d.) Whenever a water main crosses a sewer, the bottom of the water main must be at least

    eighteen (18) inches above the crown of the sewer for all portions of the water main located less than ten (10) feet from the sewer.

    e.) When it is impossible to accomplish the vertical separation required above, both the

    water main and the sewer must be constructed of water main materials and the sewer must be pressure tested for water tightness at the maximum expected surcharge head before backfilling. Wherever the water main is less than ten (10) feet from the sewer, a full twenty (20) foot length of water main pipe shall be centered at the point of sewer crossing. Rubber gasketed sewer will not be accepted as a water main quality material.

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    f.) In addition to the above, when it is necessary that a water main cross under a sewer the bottom of the sewer must be at least eighteen (18) inches above the crown of the water main for all portions of the water main located less than ten (10) feet from the sewer. The sewer must also be supported to prevent settling and breaking of the water main.

    Water mains and services shall have a minimum cover of six (6) feet, and a maximum cover of eight (8) feet from the top of the pipe to the finished ground surface. Any variation from this policy is at the discretion of the Water Division engineering staff.

    g.) Water mains and services with less than five-foot (5) of cover shall be insulated. A -inch thick closed cell foam insulation is to be wrapped around shallow services and then an Insulation board (polystyrene) is to be laid, over top of main and service. The 4x 8 standard boards shall orientate to provide a minimum coverage of eighteen (18) inches beyond the outside edge of the pipe being, covered. The insulation board shall have a minimum R-value of R-9 and comply with ASTM C 578-92 Type 1X. One 2-inch thick sheet of insulation is equivalent of 1 foot of ground cover when determining thickness requirements. (See Standard Detail)

    h) All water main, and services to the property line, shall have a plastic caution tape placed in the trench approximately 3 feet above the top of the pipe to warn excavators of the nearby pipe. The tape shall be yellow with black lettering and 4 inches in width.

    12.06 Pipe Fitting Specifications

    Pipe fittings shall be 250 PSI rated cast iron or ductile iron, fully complying with the provisions

    of AWWA Standard C110 (ANSI Standard A21.10). Ductile iron "compact" fittings, rated at

    350 PSI, are acceptable provided they fully comply with the AWWA Standard C153 (ANSI

    Standard A21.53).

    All fittings shall be cement mortar lined in accordance with the provisions of AWWA Standard

    C104 (ANSI Standard A21.4).

    Fitting joints shall be mechanical type, fully complying with the provisions of AWWA Standard

    C111 (ANSI Standard A21.11). Fittings shall be furnished with ductile iron retainer glands and all joint accessories.

    12.07 Dead Ends

    All dead ends on newly laid mains shall be closed with cast iron or ductile iron plugs and caps. Where a dead end is not equipped with a fire hydrant, the last pipe shall be fitted with a bleeder plug and valve. The valve shall be a two (2) inch gate valve. A cast iron valve box shall be provided for the bleeder valve as well as the (2) inch 90-degree bend. The valve-operating wheel shall be readily accessible for operation through the valve box opening, which shall be set flush with the finished surface. Detailed drawings can be obtained from the

    Rockford Water Division. In order to reduce cost and allow future main extension to be made without interruption of water service, extensions should, where possible, end one (1) pipe length beyond a control valve. The stub end must be capped or plugged but the bleeder valve may be located in the control valve vault, provided no service connections are made to the stub.

    12.08 Thrust Blocking

    The parameters involved in the design of thrust blocks shall include pipe size, maximum system pressure, angle of the bend, (or the configuration of the fitting), and the horizontal bearing strength of the soil. Bearing surface should, where possible, be placed against

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    undisturbed soil. Where it is not possible, the fill between the bearing surface and undisturbed soil must be compacted to at least 90% Standard Proctor density. Thrust blocks shall be used wherever there is a change in horizontal direction, and on dead ends. On vertical down and vertical up bends, restrained glands are required (see Section

    12.16 Restrained Glands). Thrust block size shall be determined by Rockford Water

    Division. Thrust blocks shall be P.C. concrete, a minimum twelve (12) inches thick, formed between the pipe, or fitting and the undisturbed trench wall, and shall be, anchored in such a manner that the pipe and fitting joints will be...

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